Systems and methods for cooling a drive end bearing

ABSTRACT

Certain embodiments provide systems and methods for cooling a drive end bearing. The system may include an alternator including a drive end bearing, a drive end fan and a front housing face. The drive end fan may include a shaft aperture and auxiliary air flow inlet apertures positioned circumferentially around the shaft aperture. The front housing face may include auxiliary fins coupled to the drive end bearing. The auxiliary fins may protrude from the front housing face. The auxiliary fins may be arrayed axially on the front housing face. In various embodiments, the drive end fan is rotated to draw air through the auxiliary air flow inlet apertures and adjacent to at least a portion of auxiliary fins of the front housing face. The at least a portion of the auxiliary fins transfers heat from the drive end bearing to the air.

CROSS-REFERENCE TO RELATED APPLICATIONS/INCORPORATION BY REFERENCE

[Not Applicable]

FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

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MICROFICHE/COPYRIGHT REFERENCE

[Not Applicable]

FIELD OF THE INVENTION

Certain embodiments of the invention relate to systems and methods forcooling a drive end bearing in an alternator. More specifically, certainembodiments provide a drive end fan comprising auxiliary air flow inletapertures for drawing ambient temperature air into the drive end fan andradially outward along auxiliary bearing cooling system air pathsadjacent to auxiliary fins of a front housing face such that theauxiliary fins transfer drive end bearing heat to the air flow, whichcools the drive end bearing.

BACKGROUND OF THE INVENTION

Alternators are electromechanical devices that convert mechanical energyto alternating current. FIG. 1 is a vertical cross-sectional view, takenalong the longitudinal axis of a rotor assembly shaft 130, of anexemplary alternator 100 as is known in the art. Referring to FIG. 1,the exemplary alternator 100 may comprise, as an example, a drive end101, a rear end 102, sides 103, conventional main air flow paths 104, adrive end fan 110, a drive end bearing 120, a rotor assembly shaft 130,stator windings 140, rectifiers 150, and a front housing face 160, amongother things. The front housing face 160 may comprise conventional fins161, for example.

The rotor assembly shaft 130 may be connected with, for instance, apulley, not shown, that may be driven by the engine of a motor vehicle,also not shown. The drive end fan 110 may be mounted on the shaft 130,for rotation with the shaft 130, at the drive end 101. Rotation of thedrive end fan 110 pulls air through the alternator 100 along theconventional main air flow paths 104 for cooling the components of thealternator 100. Ambient temperature air enters the alternator 100 at therear end 102 and is expelled from the sides 103 at the drive end 101 ofthe alternator 100 by the drive end fan 110.

More specifically, the air entering the alternator 100 at the rear end102 flows adjacent to the rectifiers 150, the stator windings 140 andthe drive end bearing 120 along the conventional main air flow paths104. As the ambient temperature air is pulled adjacent to the rectifiers150, heat from the rectifiers is transferred to the air flow, whichcools the rectifiers 150. The rectifier-warmed air flow may then bepulled adjacent to the stator windings 140, where additional heat istransferred to the air flow, thereby cooling the stator windings 140.The stator winding and rectifier-warmed air flow may then be pulledadjacent to the drive end bearing 120, where additional heat istransferred to the air flow via conventional fins 161 of a front housingface 160. The drive end bearing, stator winding and rectifier-warmed airflow may then be expelled from the sides 103 at the drive end 101 of thealternator 100 by the drive end fan 110.

Current conventional main air flow paths 104 in alternators 100 havelimited effectiveness cooling the drive end bearing 120 due to the airflowing over the conventional fins 105 being pre-heated by therectifiers 150 and stator windings 140. The ineffective cooling of thedrive end bearing 120 reduces the life of the drive end bearing 120.

As such, there is a need for providing improved systems and methods forcooling a drive end bearing 120 in an alternator 100.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of skill in the art, throughcomparison of such systems with some aspects of the present invention asset forth in the remainder of the present application with reference tothe drawings.

BRIEF SUMMARY OF THE INVENTION

Systems and methods for cooling a drive end bearing in an alternator areprovided, substantially as shown in and/or described in connection withat least one of the figures, as set forth more completely in the claims.

These and other advantages, aspects and novel features of the presentinvention, as well as details of an illustrated embodiment thereof, willbe more fully understood from the following description and drawings.

BRIEF DESCRIPTION OF SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a vertical cross-sectional view, taken along the longitudinalaxis of a rotor assembly shaft, of an exemplary alternator as is knownin the art.

FIG. 2 is a vertical cross-sectional view, taken along the longitudinalaxis of a rotor assembly shaft, of an exemplary alternator comprising anauxiliary bearing cooling system air path in accordance with anembodiment of the present invention.

FIG. 3 is a partially exploded perspective view of an exemplary driveend fan and front housing face of an exemplary alternator in accordancewith an embodiment of the present invention.

FIG. 4 is a front end elevational view of an exemplary front housingface in accordance with an embodiment of the present invention.

FIG. 5 is a rear perspective view of an exemplary drive end fan inaccordance with an embodiment of the present invention.

FIG. 6 is a rear end elevational view of an exemplary drive end fan inaccordance with an embodiment of the present invention.

FIG. 7 is a front end elevational view of an exemplary drive end fan inaccordance with an embodiment of the present invention.

FIG. 8 is a flow diagram that illustrates exemplary steps for cooling adrive end bearing in accordance with an embodiment of the presentinvention.

The foregoing summary, as well as the following detailed description ofcertain embodiments of the present invention, may be better understoodwhen read in conjunction with the appended drawings. For the purpose ofillustrating the invention, certain embodiments are shown in thedrawings. It should be understood, however, that the present inventionis not limited to the arrangements and instrumentality shown in theattached drawings.

DETAILED DESCRIPTION

Certain embodiments of the invention may be found in systems and methodsfor cooling a drive end bearing 120 in an alternator 100. Morespecifically, certain embodiments provide a drive end fan 110 comprisingauxiliary air flow inlet apertures 114 for drawing ambient temperatureair into the drive end fan 110 and radially outward along auxiliarybearing cooling system air paths 105 adjacent to auxiliary fins 162 of afront housing face 160 such that the auxiliary fins 162 transfer driveend bearing heat to the air flow, which cools the drive end bearing 120.

Various embodiments provide an alternator 100 comprising a drive endbearing 120, a drive end fan 110 and a front housing face 160. The driveend fan 110 may comprise a shaft aperture 112 and a plurality ofauxiliary air flow inlet apertures 114 positioned circumferentiallyaround the shaft aperture 112. The front housing face may comprise aplurality of auxiliary fins 162 coupled to the drive end bearing 120.The plurality of auxiliary fins 162 may protrude from the front housingface 160. The plurality of auxiliary fins 162 may be arrayed axially onthe front housing face 160.

Certain embodiments provide a method 800 for cooling a drive end bearing120. The method 800 may comprise rotating 810 a drive end fan 110. Themethod 800 may comprise drawing 820 air through a plurality of auxiliaryair flow inlet apertures 114 of the drive end fan 110. The method 800may comprise pulling 830 the air across a plurality of auxiliary fins162 arrayed axially on a front housing face 160 to transfer drive endbearing heat to the air. The method 800 may comprise expelling 840 thedrive end bearing-heated air from an alternator 100 by the drive end fan110.

Although certain embodiments in the foregoing description may be shownwith brushless alternators as illustrated in FIGS. 1-2, for example,unless so claimed, the scope of various aspects of the present inventionshould not be limited to brushless alternators and may additionallyand/or alternatively be applicable to brush-type alternators, or anysuitable alternator.

FIG. 2 is a vertical cross-sectional view, taken along the longitudinalaxis of a rotor assembly shaft 130, of an exemplary alternator 100comprising an auxiliary bearing cooling system air path 105 inaccordance with an embodiment of the present invention. Referring toFIG. 2, the exemplary alternator 100 may comprise, as an example, adrive end 101, a rear end 102, sides 103, conventional main air flowpaths 104, auxiliary bearing cooling system air paths 105, a drive endfan 110, a drive end bearing 120, a rotor assembly shaft 130, statorwindings 140, rectifiers 150, and a front housing face 160, among otherthings. The drive end fan 110 may comprise fan blades 111, a shaftaperture 112, a fan hub 113, auxiliary air flow inlet apertures 114, afan face depression 115 and/or fan face slots 116, for example. Thefront housing face 160 may comprise conventional fins 161 and auxiliaryfins 162, for example.

The rotor assembly shaft 130 may be connected with, for instance, apulley 200 that may be driven by the engine of a motor vehicle, notshown. The drive end fan 110 may be mounted on the shaft 130, forrotation with the shaft 130, at the drive end 101.

Certain embodiments provide the drive end fan 110 comprises fan blades111 (as illustrated in FIGS. 3 and 5-6, for example), a shaft aperture112 (as illustrated in FIGS. 3 and 5-7, for example), a fan hub 113,auxiliary air flow inlet apertures 114, a fan face depression 115 and/orfan face slots 116 (as illustrated in FIG. 7, for example), among otherthings. The drive end fan 110 may be aluminum, plastic, steel, or anysuitable material. The shaft aperture 112 extends through the drive endfan 110. The shaft aperture 112 is positioned substantially at thecenter of the drive end fan 110 and is configured to receive one or moreof the fan hub 113 and the rotor assembly shaft 130.

In various embodiments, a fan hub 113 is integrated with the drive endfan 110 at the shaft aperture 112 or operable to fit within the shaftaperture 112. In certain embodiments, the fan hub 113 may bemanufactured using substantially the same material as the rotor assemblyshaft 130 such that the thermal expansion properties of the rotorassembly shaft 130 and the fan hub 130 are substantially matched. Forexample, in certain embodiments, the fan hub 130 and the rotor assemblyshaft 130 may be steel, or any suitable material. In variousembodiments, the fan hub 113 and the rotor assembly may be manufacturedusing different materials. In certain embodiments, the fan hub 113 maybe omitted and the rotor assembly shaft 130 can be attached to the driveend fan 110 within the shaft aperture 112.

In certain embodiments, the fan blades 111 may be positioned toward thecenter of the drive end fan 100 and extend radially outward (asillustrated in FIGS. 5-6, for example). Various embodiments provide thatwhen the drive end fan 110 is rotating, air pressure levels increasefrom the center of the drive end fan 110 radially outward to the sides103 of alternator 100.

The drive end fan 110 may comprise auxiliary air flow inlet apertures114 that extend through the drive end fan 110. The auxiliary air flowinlet apertures 114 can be positioned circumferentially around the shaftaperture 112 and/or the fan hub 113. In certain embodiments, theauxiliary air flow inlet apertures 114 may be substantially the samesize and evenly spaced about the shaft aperture 112 and/or the fan hub113; however, auxiliary air flow inlet apertures 114 of different sizesand spacing are also contemplated. In various embodiments, sixteenauxiliary air flow inlet apertures 114 (as illustrated in FIG. 3, forexample) may be included in the drive end fan 110; however, more or lessauxiliary air flow inlet apertures 114 are also contemplated (asillustrated in FIGS. 2 and 6-7, for example).

In various embodiments, rotation of the drive end fan 110 pulls airthrough the auxiliary air flow inlet apertures 114 and adjacent to thefront housing face 160 along the auxiliary bearing cooling system airpaths 105 for cooling the drive end bearing 120 via the auxiliary fins162. For example, the drive end bearing 120 may be coupled to auxiliaryfins 162 in such a way that heat from the drive end bearing 120 istransferred to the auxiliary fins 162. As such, by transferring heatfrom the auxiliary fins 162 to the air, the temperature of the drive endbearing 120 coupled to the auxiliary fins 162 is decreased.

More specifically, rotation of the drive end fan 110 pulls ambienttemperature air behind a pulley 200, for example, and through theauxiliary air flow inlet apertures 114 into an otherwise stagnant airpocket in front of the drive end bearing 120. The fan face depression115 may be positioned around the shaft aperture 112 of the drive end fan110 and provide an opening for air to flow behind a pulley 200 andthrough the auxiliary air flow inlet apertures 114 as the drive end fan110 is rotating. The lower air pressure at the auxiliary air flow inletapertures 114 allows the drive end fan 110 to draw the air radiallyoutward past auxiliary fins 162 arrayed axially on the front housingface 160. The auxiliary fins 162 transfer drive end bearing heat to theauxiliary bearing cooling system air flow, thereby cooling the drive endbearing 120. The auxiliary bearing cooling system air flow may then beexpelled from the sides 103 at the drive end 101 of the alternator 100by the drive end fan 110.

In certain embodiments, rotation of the drive end fan 110 pulls airthrough the alternator 100 along the conventional main air flow paths104 for cooling the components of the alternator 100. Ambienttemperature air enters the alternator 100 at the rear end 102 and isexpelled from the sides 103 at the drive end 101 of the alternator 100by the drive end fan 110.

More specifically, the air entering the alternator 100 at the rear end102 flows adjacent to the rectifiers 150, the stator windings 140 andthe drive end bearing 120 along the conventional main air flow paths104. As the ambient temperature air is pulled adjacent to the rectifiers150, heat from the rectifiers is transferred to the air flow, whichcools the rectifiers 150. The rectifier-warmed air flow may then bepulled adjacent to the stator windings 140, where additional heat istransferred to the air flow, thereby cooling the stator windings 140.The stator winding and rectifier-warmed air flow may then be pulledadjacent to the drive end bearing 120, where additional heat istransferred to the air flow via conventional fins 161 of a front housingface 160. The drive end bearing, stator winding and rectifier-warmed airflow may then be expelled from the sides 103 at the drive end 101 of thealternator 100 by the drive end fan 110.

In various embodiments, air pulled along the auxiliary bearing coolingsystem air paths 105 may join air from the conventional main air flowpaths 104 at the drive end fan 110 prior to being expelled from thesides 103 at the drive end 101 of the alternator 100 by the drive endfan 110.

FIG. 3 is a partially exploded perspective view of an exemplary driveend fan 110 and front housing face 160 of an exemplary alternator 100 inaccordance with an embodiment of the present invention. Referring toFIG. 3, the drive end fan 110 comprises fan blades 111, a shaft aperture112, a fan hub 113, auxiliary air flow inlet apertures 114, and a fanface depression 115, for example.

The front housing face 160 may comprise conventional fins 161 andauxiliary fins 162, for example. In various embodiments, theconventional fins 161 may be cut into the front housing face 160 suchthat the conventional main air flow is pulled through the front housingface 160 between the conventional fins 161 by the drive end fan 110. Thefront housing face 160 comprising the conventional fins 161 cut into thefront housing face 160 may be manufactured using a die case mold, forexample, or any suitable manufacturing method. The air flowing betweenthe conventional fins 161 may provide cooling to the drive end bearing120, although the cooling may be limited due to the air flowing alongthe conventional main air flow paths 104 being pre-heated by therectifiers 150 and stator windings 140.

In certain embodiments, the auxiliary fins 162 may protrude from thefront housing face 160 and can be arrayed axially on the front housingface 160. The drive end bearing 120 may be cooled via the auxiliary fins162 as the drive end fan 110 rotates to pull ambient temperature airthrough the auxiliary air flow inlet apertures 114 and across theauxiliary fins 162 along the auxiliary bearing cooling system air paths105. For example, the drive end bearing 120 may be coupled to auxiliaryfins 162 in such a way that heat from the drive end bearing 120 istransferred to the auxiliary fins 162. As such, by transferring heatfrom the auxiliary fins 162 to the air, the temperature of the drive endbearing 120 coupled to the auxiliary fins 162 is decreased.

The drive end fan 110 and the front housing face 160 illustrated in FIG.3 shares various characteristics with the drive end fan 110 and thefront housing face 160 illustrated in FIG. 2 as described above.

FIG. 4 is a front end elevational view of an exemplary front housingface 160 in accordance with an embodiment of the present invention.Referring to FIG. 4, the front housing face 160 comprises conventionalfins 161 and auxiliary fins 162, for example.

The front housing face 160 illustrated in FIG. 4 shares variouscharacteristics with the front housing face 160 illustrated in FIGS. 2-3as described above.

FIG. 5 is a rear perspective view of an exemplary drive end fan 110 inaccordance with an embodiment of the present invention. FIG. 6 is a rearend elevational view of an exemplary drive end fan 110 in accordancewith an embodiment of the present invention. Referring to FIGS. 5-6, thedrive end fan 110 comprises fan blades 111, a shaft aperture 112, a fanhub 113, and auxiliary air flow inlet apertures 114.

The drive end fan 110 illustrated in FIGS. 5-6 shares variouscharacteristics with the drive end fan 110 illustrated in FIGS. 2-3 asdescribed above.

FIG. 7 is a front end elevational view of an exemplary drive end fan 110in accordance with an embodiment of the present invention. Referring toFIG. 7, the drive end fan 110 comprises a shaft aperture 112, auxiliaryair flow inlet apertures 114, and fan face slots 116, for example. Invarious embodiments, the fan face slots 116 may be grooves cut into, butnot through, the front face of the drive end fan 110 such that anopening is provided for air to flow behind a pulley 200 and through theauxiliary air flow inlet apertures 114 as a drive end fan 110 isrotating. For example, certain pulley types may be positionedsubstantially flush to the front face of the drive end fan 110. As such,in order for ambient temperature air to access the auxiliary air flowinlet apertures 114 when a flush mounted pulley is used, certainembodiments provide fan face slots 116 as illustrated in FIG. 7 and/or afan face depression 115 as illustrated in FIGS. 2-3.

In various embodiments, the fan face slots 116 may be in addition to oran alternative to the fan face depression illustrated in FIGS. 2-3, forexample. In certain embodiments, the auxiliary air flow inlet apertures114 are positioned within the fan face slots 116. In variousembodiments, the fan face slots 116 are positioned circumferentiallyaround the shaft aperture 112 and/or the fan hub 113. In certainembodiments, the fan face slots 116 may be substantially the same size,same shape, and evenly spaced about the shaft aperture 112 and/or thefan hub 113; however, fan face slots 116 of different sizes, shapes andspacing are also contemplated. In various embodiments, the number of fanface slots 116 corresponds with the number of auxiliary air flow inletapertures 114. In certain embodiments, eight fan face slots 116 may beincluded in the drive end fan 110; however, more or less fan face slots116 are also contemplated.

The drive end fan 110 illustrated in FIG. 7 shares variouscharacteristics with the drive end fan 110 illustrated in FIGS. 2-3 and5-6 as described above.

FIG. 8 is a flow diagram 800 that illustrates exemplary steps 810-840for cooling a drive end bearing 120 in accordance with an embodiment ofthe present invention. Referring to FIG. 8, there is shown a flowdiagram 800, which illustrates exemplary steps 810-840 for cooling adrive end bearing 120. At step 810, a drive end fan 110 is rotated. Atstep 820, ambient temperature air is drawn through auxiliary air flowinlet apertures 114 of the drive end fan 110. At step 830, the air ispulled across auxiliary fins 162 arrayed axially on a front housing face160 to transfer drive end bearing heat to the air. At step 840, thedrive end bearing-heated air is expelled from sides 103 at a drive end101 of an alternator 100 by the drive end fan 110. Although the methodis described with reference to the exemplary elements of the systemsdescribed above, it should be understood that other implementations arepossible.

At step 810, a drive end fan 110 is rotated. In certain embodiments, thedrive end fan 110 is positioned at a drive end 101 of an alternator 100and is connected to a rotor assembly shaft 130 of the alternator 100,for rotation with the shaft 130. The rotor assembly shaft 130 may beconnected with, for instance, a pulley 200 that may be driven by theengine of a motor vehicle, not shown, for example.

At step 820, ambient temperature air is drawn through auxiliary air flowinlet apertures 114 of the drive end fan 110. In various embodiments,rotation of the drive end fan 110 pulls ambient temperature air behind apulley 200, for example, and through the auxiliary air flow inletapertures 114 into an otherwise stagnant air pocket in front of thedrive end bearing 120. A fan face depression 115 or fan face slots 116may provide an opening for air to flow behind a pulley 200 and throughthe auxiliary air flow inlet apertures 114 as a drive end fan 110 isrotating. For example, certain pulley types may be positionedsubstantially flush to the front face of the drive end fan 110. As such,in order for ambient temperature air to access the auxiliary air flowinlet apertures 114 when a flush mounted pulley is used, certainembodiments provide fan face slots 116 as illustrated in FIG. 7 and/or afan face depression 115 as illustrated in FIGS. 2-3.

At step 830, the air is pulled across auxiliary fins 162 arrayed axiallyon a front housing face 160 to transfer drive end bearing heat to theair. Various embodiments provide that when the drive end fan 110 isrotating, air pressure levels increase from the center of the drive endfan 110 radially outward to the sides 103 of the alternator 100. Thelower air pressure at the auxiliary air flow inlet apertures 114 allowsthe drive end fan 110 to draw the air radially outward past auxiliaryfins 162. In certain embodiments, the auxiliary fins 162 may protrudefrom the front housing face 160 and can be arrayed axially on the fronthousing face 160. The drive end bearing 120 may be cooled via theauxiliary fins 162 as the drive end fan 110 rotates to pull ambienttemperature air through the auxiliary air flow inlet apertures 114 andacross the auxiliary fins 162 along the auxiliary bearing cooling systemair paths 105.

At step 840, the drive end bearing-heated air is expelled from sides 103at a drive end 101 of an alternator 100 by the drive end fan 110. Invarious embodiments, air pulled along the auxiliary bearing coolingsystem air paths 105 may join air from conventional main air flow paths104 at the drive end fan 110 prior to being expelled from the sides 103at the drive end 101 of the alternator 100 by the drive end fan 110.

Various embodiments provide an alternator 100 comprising a drive endbearing 120, a drive end fan 110 and a front housing face 160. The driveend fan 110 may comprise a shaft aperture 112 and a plurality ofauxiliary air flow inlet apertures 114 positioned circumferentiallyaround the shaft aperture 112. The front housing face may comprise aplurality of auxiliary fins 162 coupled to the drive end bearing 120.The plurality of auxiliary fins 162 may protrude from the front housingface 160. The plurality of auxiliary fins 162 may be arrayed axially onthe front housing face 160.

In certain embodiments, the drive end fan 110 is rotated to draw airthrough the plurality of auxiliary air flow inlet apertures 114 andadjacent to at least a portion of the plurality of auxiliary fins 162 ofthe front housing face 160.

In various embodiments, the air drawn through the plurality of auxiliaryair flow inlet apertures 114 is ambient temperature air.

In certain embodiments, the at least a portion of the plurality ofauxiliary fins 162 transfers heat from the drive end bearing 120 to theair.

In various embodiments, each of the plurality of auxiliary air flowinlet apertures 114 is substantially a same size.

In certain embodiments, each of the plurality of auxiliary air flowinlet apertures 114 is evenly spaced about the shaft aperture 112.

In various embodiments, the plurality of auxiliary air flow inletapertures 114 are at least one of eight auxiliary air flow inletapertures and sixteen auxiliary air flow inlet apertures.

In certain embodiments, the air drawn through the plurality of auxiliaryair flow inlet apertures 114 and adjacent to the at least a portion ofthe plurality of auxiliary fins 162 of the front housing face 160 isexpelled from the alternator 100 by the drive end fan 110.

In various embodiments, the alternator 100 comprises a rear end 102. Theair from the rear end 102 is drawn through the alternator 100 and joinsthe air drawn through the plurality of auxiliary air flow inletapertures 114 prior to being expelled from the alternator 100 by thedrive end fan 110.

In certain embodiments, the drive end fan 110 comprises a front face(FIGS. 3 and 7) and a rear face (FIGS. 5-6). The front face (FIGS. 3 and7) comprises a plurality of fan face slots 116 positionedcircumferentially around the shaft aperture 112 (as illustrated in FIG.7). Each of the plurality of the auxiliary air flow inlet apertures 114is positioned within a corresponding one of the plurality of fan faceslots 116.

In various embodiments, the drive end fan 110 comprises a front face(FIGS. 3 and 7) and a rear face (FIGS. 5-6). The front face (FIGS. 3 and7) comprises a fan face depression 115 positioned around the shaftaperture 112 (as illustrated in FIG. 3). The plurality of auxiliary airflow inlet apertures 114 are positioned within the fan face depression115.

Certain embodiments provide a method 800 for cooling a drive end bearing120. The method 800 may comprise rotating 810 a drive end fan 110. Themethod 800 may comprise drawing 820 air through a plurality of auxiliaryair flow inlet apertures 114 of the drive end fan 110. The method 800may comprise pulling 830 the air across a plurality of auxiliary fins162 arrayed axially on a front housing face 160 to transfer drive endbearing heat to the air. The method 800 may comprise expelling 840 thedrive end bearing-heated air from an alternator 100 by the drive end fan110.

In various embodiments, the air drawn through the plurality of auxiliaryair flow inlet apertures 114 is ambient temperature.

In certain embodiments, the plurality of auxiliary air flow inletapertures 114 are positioned circumferentially around a shaft aperture112 of the drive end fan 110.

In various embodiments, each of the plurality of auxiliary air flowinlet apertures 114 is substantially a same size.

In certain embodiments, each of the plurality of auxiliary air flowinlet apertures 114 is evenly spaced about the shaft aperture 112.

In various embodiments, the method 800 may comprise drawing air from arear end 102 of the alternator 100 through the alternator 100. The airdrawn from the rear end 102 of the alternator 100 and through thealternator 100 may join the air drawn through the plurality of auxiliaryair flow inlet apertures 114 prior to being expelled from the alternator100 by the drive end fan 110.

In certain embodiments, the method 800 may comprise drawing the airbehind a pulley 200 prior to drawing the air through the plurality ofauxiliary air flow inlet apertures 114 of the drive end fan 110.

In various embodiments, the air drawn behind the pulley 200 is drawnthrough a plurality of fan face slots 116 positioned circumferentiallyaround a shaft aperture 112 of the drive end fan 110. Each of theplurality of the auxiliary air flow inlet apertures 114 may bepositioned within a corresponding one of the plurality of fan face slots116.

In certain embodiments, the air drawn behind the pulley 200 is drawnthrough a fan face depression 115 positioned around a shaft aperture 112of the drive end fan 110. The plurality of auxiliary air flow inletapertures 114 are positioned within the fan face depression 115.

While the present invention has been described with reference to certainembodiments, it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted withoutdeparting from the scope of the present invention. In addition, manymodifications may be made to adapt a particular situation or material tothe teachings of the present invention without departing from its scope.Therefore, it is intended that the present invention not be limited tothe particular embodiment disclosed, but that the present invention willinclude all embodiments falling within the scope of the appended claims.

1-20. (canceled)
 21. An alternator comprising: a drive end; a rear end opposite the drive end; a drive end bearing; a drive end fan at the drive end, the drive end fan comprising a shaft aperture and a plurality of auxiliary air flow inlet apertures positioned circumferentially around the shaft aperture; and a front housing face adjacent to the drive end fan, the front housing face comprising a plurality of auxiliary fins coupled to the drive end bearing, the plurality of auxiliary fins protruding from the front housing face, and the plurality of auxiliary fins arrayed axially on the front housing face.
 22. The alternator according to claim 21, wherein the drive end fan is rotated to draw air into the alternator via the plurality of auxiliary air flow inlet apertures and adjacent to at least a portion of the plurality of auxiliary fins of the front housing face.
 23. The alternator according to claim 22, wherein the air drawn into the alternator via the plurality of auxiliary air flow inlet apertures is ambient temperature air.
 24. The alternator according to claim 23, wherein the at least a portion of the plurality of auxiliary fins transfers heat from the drive end bearing to the air.
 25. The alternator according to claim 21, wherein each of the plurality of auxiliary air flow inlet apertures is substantially a same size.
 26. The alternator according to claim 21, wherein each of the plurality of auxiliary air flow inlet apertures is evenly spaced about the shaft aperture.
 27. The alternator according to claim 21, wherein the plurality of auxiliary air flow inlet apertures are at least one of eight auxiliary air flow inlet apertures and sixteen auxiliary air flow inlet apertures.
 28. The alternator according to claim 22, wherein the air drawn into the alternator via the plurality of auxiliary air flow inlet apertures and adjacent to the at least a portion of the plurality of auxiliary fins of the front housing face is expelled from the alternator by the drive end fan.
 29. The alternator according to claim 28, wherein air from the rear end is drawn through the alternator and joins the air drawn into the alternator via the plurality of auxiliary air flow inlet apertures prior to being expelled from the alternator by the drive end fan.
 30. The alternator according to claim 21, wherein the drive end fan comprises a front face and a rear face, the front face comprising a plurality of fan face slots positioned circumferentially around the shaft aperture, wherein each of the plurality of the auxiliary air flow inlet apertures is positioned within a corresponding one of the plurality of fan face slots.
 31. The alternator according to claim 21, wherein the drive end fan comprises a front face and a rear face, the front face comprising a fan face depression positioned around the shaft aperture, wherein the plurality of auxiliary air flow inlet apertures are positioned within the fan face depression.
 32. The alternator according to claim 21, wherein the drive end fan comprises a front face and a rear face opposite the front face, the rear face comprising a plurality of fan blades, and the rear face facing the front housing face.
 33. A method for cooling a drive end bearing, the method comprising: rotating a drive end fan at a drive end of an alternator; drawing air into the alternator via a plurality of auxiliary air flow inlet apertures of the drive end fan; pulling the air across a plurality of auxiliary fins arrayed axially on a front housing face adjacent the drive end fan to transfer drive end bearing heat to the air; and expelling the drive end bearing-heated air from the alternator by the drive end fan.
 34. The method according to claim 33, wherein the air drawn into the alternator via the plurality of auxiliary air flow inlet apertures is ambient temperature.
 35. The method according to claim 33, wherein the plurality of auxiliary air flow inlet apertures are positioned circumferentially around a shaft aperture of the drive end fan.
 36. The method according to claim 35, wherein each of the plurality of auxiliary air flow inlet apertures is substantially a same size.
 37. The method according to claim 35, wherein each of the plurality of auxiliary air flow inlet apertures is evenly spaced about the shaft aperture.
 38. The method according to claim 33, comprising drawing air from a rear end of the alternator through the alternator, wherein the air drawn from the rear end of the alternator and through the alternator joins the air drawn into the alternator via the plurality of auxiliary air flow inlet apertures prior to being expelled from the alternator by the drive end fan, wherein the rear end is opposite the drive end of the alternator.
 39. The method according to claim 33, comprising drawing the air behind a pulley prior to drawing the air into the alternator via the plurality of auxiliary air flow inlet apertures of the drive end fan.
 40. The method according to claim 39, wherein the air drawn behind the pulley is drawn through a plurality of fan face slots positioned circumferentially around a shaft aperture of the drive end fan, wherein each of the plurality of the auxiliary air flow inlet apertures is positioned within a corresponding one of the plurality of fan face slots.
 41. The method according to claim 39, wherein the air drawn behind the pulley is drawn through a fan face depression positioned around a shaft aperture of the drive end fan, wherein the plurality of auxiliary air flow inlet apertures are positioned within the fan face depression.
 42. The method according to claim 33, wherein the drive end fan comprises a front face and a rear face opposite the front face, the rear face comprising a plurality of fan blades, and the rear face facing the front housing face. 